The present invention relates to an improved retainer for holding balls in a ball bearing and to a method of making the same.
Prior art retainers used to hold balls in ball bearings are usually made by a press-forming operation utilizing steel components. In accordance with the prior art method depicted in FIG. 1, metallic retainer pieces B and C are formed to have a generally undulating shape. Piece B (as well as mating piece C as indicated by the parenthetical reference numeral (C)) has a series of relatively flat portions E arranged in alternating sequence with a series of concave portions. Balls A are placed in the concave portions of the piece B (or piece C, as the case may be), the piece B (or the piece C) also being placed between inner and outer races (not shown) so that the balls A are held in position. Mating piece C (or piece B) is then placed on top of piece B (or piece C) with the concave portions of the two mating pieces aligned to form cavities D which accommodate the respective balls A. The retainer pieces B and C are then welded together at the flat portions E thereof or fastened together by caulked pins F as shown in FIG. 2.
Unfortunately, the conventional steel-made, wave-shaped retainers for ball bearings--whether assembled by welding or caulked pins as described above--suffer from several problems or deficiencies. For instance, a metal powder resulting from the welding operation or the caulking of the pins frequently sticks to a race surface (a surface of a groove of the race). Consequently, an extra step is required to wash away the metal powder.
Another problem occurs in the prior art methods in that an oxidized film is easily formed on race surfaces during the welding process, thereby preventing the balls from rolling smoothly. Moreover, assembly of the bearings in accordance with the prior art methods is a fairly time consuming process, especially the placement of the retainer pieces B and C in mating relation during the assembly process.
The conventional prior art methods unfortunately produce bearings which are noisy in use and bearings which are heavy.
In view of the foregoing, it is an object of the present invention to provide a retainer formed from an appropriate non-metallic material for use in retaining ball bearings.
An advantage of the present invention is the provision of a method of making retainers for ball bearings in which race surfaces are not contaminated during the manufacturing process.
Another advantage of the present invention is the provision of light-weight, silent retainers for ball bearings.